Feasibility Evaluation of a Self-guided Exposure-based Digital Intervention for Health Anxiety

The Short health anxiety inventory - 14 item (SHAI-14). Higher scores indicate greater severity of health anxiety. Scores range from 0 to 42.

Will be determined by the amount of exposure exercises reported in the program and in a weekly questionnaire. Acceptable level of adherence will be set to at least 50 % of participants working actively with exposure a majority of the days during a week for 4 weeks or more.

Will be determined by the number of modules completed by the participants.

Will be determined by the number of different types of exposure exercises performed by participants. At the end of the program, participants will answer yes or no to whether they engaged in each component (type of exposure exercise) of the intervention.

Participants will be asked to state whether they had experienced any negative or unwanted effects of the treatment. If answering 'Yes', participants will be asked to specify the adverse event in free text. Adverse events will primarily be reported as the total number of reported events.

Client Satisfaction Questionnaire (CSQ-8). Scores range from 8-32 with higher scores indicating greater satisfaction. An average Client Satisfaction Questionnaire-8 score of at least 22 will provide support for the acceptability and feasibility of this intervention.

The Short health anxiety inventory - 14 item (SHAI-14). Higher scores indicate greater severity of health anxiety. Scores range from 0 to 42.

The Short health anxiety inventory - 14 item (SHAI-14). Higher scores indicate greater severity of health anxiety. Scores range from 0 to 42.

Patient Health Questionnaire - 9 Item (PHQ-9). Higher total scores indicate greater severity of depression. Scores range from 0 to 27.

Patient Health Questionnaire - 9 Item (PHQ-9). Higher total scores indicate greater severity of depression. Scores range from 0 to 27.

Patient Health Questionnaire - 9 Item (PHQ-9). Higher total scores indicate greater severity of depression. Scores range from 0 to 27.

Health Preoccupation Diagnostic Interview (HPDI). HPDI is a structured interview designed to assess Illness anxiety disorder and Somatic symptom disorder according to DSM-V criteria. HPDI will be administered via telephone.

Generalized Anxiety Disorder 7-item scale (GAD-7). Higher total scores indicate greater severity of anxiety symptoms. Scores range from 0 to 21.

Generalized Anxiety Disorder 7-item scale (GAD-7). Higher total scores indicate greater severity of anxiety symptoms. Scores range from 0 to 21.

Generalized Anxiety Disorder 7-item scale (GAD-7). Higher total scores indicate greater severity of anxiety symptoms. Scores range from 0 to 21.

Brunnsviken Brief Quality of Life Questionnaire (BBQ). A 12-item questionnaire covering six different life domains: leisure time, view on life, creativity, learning, friends and friendship, and view of self. Scores range from 0 to 96, where higher values indicate higher quality of life satisfaction.

Brunnsviken Brief Quality of Life Questionnaire (BBQ). A 12-item questionnaire covering six different life domains: leisure time, view on life, creativity, learning, friends and friendship, and view of self. Scores range from 0 to 96, where higher values indicate higher quality of life satisfaction.

The five-item version of Credibility/Expectancy Questionnaire (CEQ). The CEQ ranges from 0 to 10 points per item and 0 to 50 points in total, where a higher score reflects better treatment credibility.

The System Usability Scale (SUS). The SUS consists of ten items, with a range of 0-4 points per item. The items are summed up and calculated with a formula resulting in a total score between 0 and 100, with a higher score reflecting better system usability.

A non-validated questionnaire measuring experience working with the program. The scale comprises four questions where participant answer whether the intervention was perceived as likable, easy to understand, whether examples given felt relevant and whether functionality and information contributed to the participant feeling overwhelmed. Answers will be made on a four-point scale ranging from 0 (strongly disagree) to 3 (strongly agree). It will be optional to add a free-text comment to the responses, as well as suggestions of overall improvements.

Adherence to the exposure exercises will be determined by an online questionnaire where participant on a four point Likert scale will state to what extent they have worked with exposure: "not at all", "occasionally", "more than half of the days" and "daily".

A semi-structured interview concerning the experience of the intervention and format will be conducted via telephone